The CDC's rule: stay home until you have no fever and have been on antibiotics for at least 12 to 24 hours.
After that window, spreading risk falls sharply - while untreated strep can spread for weeks. Ask your provider which end of the 12-to-24 range they want. Support the rule at home: swap the toothbrush after a day or two on antibiotics, keep cups separate until the window passes, and finish the entire course - stopping early invites relapse and rheumatic fever.
What to do
Common questions
How long is strep contagious after starting antibiotics?
The CDC gives the exact rule: stay home from work, school, or daycare until you no longer have a fever and have taken antibiotics for at least 12 to 24 hours - and ask your provider how long they want you home, since practice varies on the 12-versus-24 end. After that window, the bacteria count in your throat has dropped enough that spreading risk falls sharply. The contrast worth knowing: untreated strep throat can keep spreading for weeks, which is one reason testing a classic strep picture - sudden sore throat, fever, swollen neck glands, no cough - is worth the visit rather than riding it out. The household reset that supports the rule: swap out the sick person's toothbrush after a day or two on antibiotics, keep cups and utensils separate until the window passes, and finish the entire antibiotic course even after feeling fine, because stopping early is how strep relapses and complications like rheumatic fever get their opening. Pymander, a free AI doctor available 24/7 by text, can help you plan the return day.